Part 3, 1911] RUTACEAE 223 



apex, dark glossy green, the margin crenulate ; flowers smaller than in the preceding 

 species, in axillary clusters of 3-10 ; petals white ; berry small, ellipsoid to oval, 3.5-6.5 

 cm. long, 2.8-5 cm. in diameter, frequently mamillate at the apex, light-yellow, the rind 

 thin, more or less roughened, the pulp abundant, greenish, acid ; seeds oval, pointed. 



Type locality: Jamaica (cultivated). 



Distribution : Cultivated ; thoroughly naturalized in tropical and subtropical regions. 

 Illustrations : Britton, N. Am. Trees /. 537 ; Bull. Hawaii Agr. Exp. Sta. 9 : pi. 3 ; Hume, 

 Citrus Fruits /. 12. 



4. Citrus Aurantium L,. Sp. PI. 782. 1753. 

 A tree 6-12 m. in height, with light-green, glabrous twigs angled toward their ends, 

 the branches smooth, grayish-brown, often armed with small, sharp thorns ; petioles 

 commonly narrowly winged, or wingless; leaves uuifoliolate, evergreen; leaflet oblong- 

 ovate to ovate or oval, 6.5-13 cm. long, 3-10 cm. broad, acute or sometimes rounded at the 

 apex, cuneate to rounded at the base, dark -green and shining above, paler beneath, entire 

 or crenulate; flowers very fragrant, in axillary clusters of 1-6; sepals more or less sharp- 

 pointed ; petals oblong, 11-18 mm. long, pure white, thick and fleshy ; berry globose or 

 subglobose, 6-9 cm. long, 6.5-9.5 cm. broad, the rind usually thin, smooth or wrinkled, 

 the pulp abundant, sweet or sour. 



Type locality : India. 



Distribution : Widely cultivated ; naturalized in tropical and subtropical regions. 

 Illustrations: Bentley & Trimen, Med. PI. 1: pi. 51; Nichols. Diet. Gard. 1 : /. 460; 

 Britton, N. Am. Trees /. 534 ; Hume. Citrus Fruits pi. 4. 



5. Citrus vulgaris Risso, Ann. Mus. Paris 20: 190. 1813. 



Citrus bigaradia Loisel. Nouv. Duham. 7 : 99. 1819. 



Citrus Aurantium vulgaris Wight & Arn. Prodr. 1 : 97. 1834. 



Citrus Aurantium bigaradia Hook. Fl. Brit. Ind. 1 : 515. 1872. 



A small tree 6-9 m. in height, the young twigs light-green, armed with sharp, alter- 

 nate thorns ; leaves unifoliolate, evergreen, alternate; leaflet ovate, 6-12 cm. long, 3.5-10 

 cm. broad, often acuminate ; petioles commonly broadly winged ; flowers in small axillary 

 cymes, sweet-scented, somewhat larger than those of the preceding ; sepals often bluntish ; 

 petals oblong, white ; berry dark-orange, or frequently reddish when mature, the rind thick, 

 more or less roughened, strongly aromatic, bitter, the pulp sour and bitter. 



Type locality: (Cultivated.) 



Distribution : Cultivated ; thoroughly naturalized in tropical and subtropical regions. 

 Illustrations : Berg & Schmidt, Off" Gew. 4 : pi. 31 e ; Bentley & Trimen, Med. PI. 1 : pi. 

 50; Britton, N. Am. Trees /. 533. 



6. Citrus decumana L. Syst. Nat. ed. 12. 2 : 508. 1767. 

 A small tree sometimes attaining a height of 12 m., with smooth grayish-brown bark ; 

 voung leaves and shoots sparsely pubescent ; petioles broadly winged ; leaflet usually ellip- 

 tic to ovate, sometimes obovate, 7-15 cm. long, acutish or rounded and frequently emarginate 

 at the apex, rounded or sometimes cuneate at the base, dark glossy green and leathery, 

 more or less crenulate ; inflorescence cymose or the flowers sometimes solitary ; flowers 

 2.5^1.4 cm. broad ; calyx cup-shaped, often somewhat pubescent, large, the sepals acute ; 

 petals oblong, rather fleshy ; berry globose or pyriform, 9-18 cm. in diameter, lemon- 

 vellow or flesh-colored, sometimes reddish, the rind usually smooth, bitter, the pulp pale- 

 yellow or reddish, acid and often somewhat bitter ; seeds more or less wedge-shaped. 



Type locality : Amboina. 



Distribution : Cultivated in tropical and subtropical regions. Naturalized in the West Indies. 

 Illustrations: Rumpf, Amb. 2: pi. 24; Nichols. Diet. Gard. 1:/. 461; Risso & Poiteau, 

 Hist. Nat. Orangers pi. 61-66 ; Hume, Citrus Fruits/. 9, 22-26, pi. 9. 



7. Citrus trifoliata L,. Sp. PI. ed. 2. 1101. 1763. 



Poncirus trifoliata Raf. Sylva Tell. 143. 1838. 



A small, low-branching tree 2-4 m. in height, the young branches angled, the older 

 ones teretish, armed with stiff, sharp, alternate thorns 2-4 cm. long, which are flattened at 

 the base; petioles winged ; leaves deciduous, trifoliolate ; leaflets elliptic or obovate, sessile, 



